The U.S. empire is headed for a cliff. Maybe it will even collapse within our lifetimes. But that collapse likely won't be the end of capitalism as a system; it has survived the collapse/diminishing of other hegemonic powers before. But what would the next hegemonic power even be? The EU? Russia? Japan?
I want to believe that the U.S. is the last stop on Mr. Capital's Wild Ride, but that seems naive.
I think the EU would be strengthened by the crises that follow America's retreat. They could also surpass American power if they wanted too. They just haven't shown any interest. Partially because it was basically designed by the US to be subservient, but also because as such a diverse coalition of states, it's hard to find common interests to act on.